OK Guy's, A little help here. I'm too far into this D30- 5:13s,ARB locker. I'm going to sleeve & gusset and go with the CRV Axle shafts. So here is my question, How big of a tire can I run comfortably? What I mean by that is crawlin aggresivly. Can I go 38s? or stick with 37s? I don't mean to sound stupid, I just thought I would get some input. Thanks for your help.

 

You are going to hear alot of opinions, mostly saying going bigger than 35's will blow up the axle. I am planning on going to 37's when my 35's die with my D30 and only planning on gussets. It really depends on your wheeling, but many have run D30's with 37's without major issues.

 

X2 here. It depends how your drive, but a built D30 (Remember that yours is a HP30 up front so it runs on the drive side of the gears rather than the coast side like a LP 30 up front would) can do just fine if you use your selectable locker correctly and keep your u-joints lubed.

Don't panic about running it. I've seen lots of people run LP30's on TJ's with 37's and that's a weaker axle. Jk's are heavier so that probably explains the upgraded front you have.

 

The internals may be stronger, but the housing is proving to be weaker.
5" longer and under a heavier vehicle = more prone to bending.
Taller C's under a heavier vehicle = more prone to bending.
And then there is the suspect metallurgy going on, which means these things are shattering with 'on-road' daily driving on stock JK's.

If you are planning on taller tires, do all of the axle upgrades you can fit in your budget, and carry spares...

 

Do it , don't do it. I say go for it cause ppl break them with either 35 or 37. Some don't.

 

I ran 38 Super Swampers on my '97 TJ for years with no problems on my Dana 30 front. I chewed up a set of gears on the Dana 35 rear, but that was my own dumb fault....to much hop trying to make a hill climb. I ran that Jeep pretty hard up here in Alaska. That axle is small, but if you drive smart it will hold up. Not ideal, just sayin.

 

I think you also need to consider the weight of the tire you plan on running...... the 40's we're currently running on our setup are actually heavier than the 42's we'll be running in the near future. In theory (or at least the way I look at it) the 42's will be less of a strain for us than the 40's.

 

I blew up (yes, you read that correctly - see pic below) my front 30 with 35's - open carrier, 4.88's, no sleeves and stock axles. I was backing up on a rock to get a better line and it let go. UGOTKERN was spotting me - he can tell you how ugly it was. I rebuilt a 30 with sleeves and gussets, but left the carrier open and kept the stock shafts, and jumped up to 37's. I haven't had a problem with it since.


One of the spider gears shot half way through the diff cover, and there was also a hole in the bottom of the pumpkin.

Based on that experience, I'm upgrading to Solid 60's in the near future. I don't want to have to worry about it every time I'm out on the rocks.

You can get away with 37's or probably even a lighter 40 (as UGOTKERN mentioned), but it's still a pretty weak axle to be turning those tires. The 5.13 ring and pinion is also pretty small in a 30, but the ARB should help a little.

JD

 

Thanks for the input guy's. I realy want to go to 38s, but also realize the difference in tire weight. I like Toyo but that is much heavier. I am going to make this D30 as strong as I can and am planning on backing it up with the Rubjcrawler for the low gear ratio.I pretty sure this front end will hold up, but you know how it is, I gotta take it to court first!

 

My sentiments exactly.